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LETTER FROM WILLIAM CLIFFORD, JEANNETTE, PA., IN RELA¬ 
TION TO MINING ACCIDENTS. 


The following letter in relation to mining accidents was written to 
Hon. George F. Huff, chairman of the Mines and Mining Committee 
of the House of Representatives, by William Clifford, of Jeannette, 
Pa., a man of considerable mining experience both in this country 
and in Europe: 

Washington, D. C., January 20, 1908. 

Hon. George F. Huff, 

Chah man Committee on Mines and Mining. 

Dear Sir: Each coal-mining country seems to have had its era 
of disaster as a prelude to good management. Ffty years ago Bel¬ 
gium was ahead of the rest of the world in scientific coal mining. 
She had gone through that “ baptism of fire ” which struck the coal 
mines of England twenty years later. 

Efficient ventilation had been provided, so as to render harmless 
all noxious gases, and in providing this ventilation another danger 
has been created. Large volumes of air which were passed through 
mines to comply with Government regulations dried the dust. The 
increasing stringency of Government regulation and a period of 
great development of coal mining in England from 1870 to 1880 was 
followed by a plentiful crop of explosions. Blantyre, Wood Pit 
Haydock, Moss Colliery, Altham, Talk O’t’Hill, third explosion, 
Newport Abercarne, Risca, Peny Graig, Ferndale, Seaham, Clifton, 
Park Slip, Swaithe Main, Llanerch, and many others, each with a 
death roll of from 100 to 250, took place. 

A little over twenty years ago Prof. William Galloway, of Cardiff, 
then an inspector of mines, commenced to write and experiment on 
mine dust. Mr. Henry Hall, inspector of mines for Lancashire, made 
a number of independent experiments in an old mine shaft, placing 
a cannon pointing upward from the bottom and firing it as a large 
quantity of dust was thrown down. A good deal of controversy 
arose because Mr. Hall’s shots were very heavy and ignition did not 
always take place. It was afterwards observed that the shaft was 
wet. 

England issued a royal commission on coal dust, of which Mr. 
Joseph Chamberlain was chairman, and its report has been published 
in a very voluminous blue book. 

Two explosions are put down as of dust per se—Pocahontas, Va., 
and Altofts, Yorkshire, England. 

Your correspondent has no hesitation in saying that Pocahontas 
was a heavy explosion of fire damp, greatly increased in force by 
large quantities of dust. 

Altofts occurred in a pit working a fiery seam of coal by advancing 
long wall method at a depth of 400 yards from the surface. The 


300 ? 5—08 



2 


MINING ACCIDENTS. 


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ignition took place at a shot fired in the main hauling way of the 
mine. The mine was old and extensive. The blast spread over a 
large area. The shot had been placed in the roof of a road which had 
been “ ripped ” or cut away several times to raise it when it had set¬ 
tled down below working height. Behind this road, at a distance of 
not more than 12 feet and much nearer in its breaking over fissures, 
was a goaf of nearly 800 acres in extent. 

The manager of this mine had within a few months of the ex¬ 
plosion read a paper before a society of which your correspondent is 
a member, explaining the difficulties experienced in this very pit by 
gas coming from the floor in the goaves beyond the first timbers. 
The remedy which he regularly applied was to sink holes along the 
floor of the working faces to tap this gas and bring it into contact 
with ventilation. 

When the pit had been cleaned up after the explosion, officers of 
the miners’ union were invited to examine it, and they concluded that 
the cause of the explosion was dust and dust only. 

I venture to say, from personal knowledge of these men, that they 
were not competent to decide the question of the origin of any ex¬ 
plosion. 

Mr. Joseph Dickinson, the oldest mine inspector in Great Britain, 
who went on behalf of the British Government to examine into the 
methods adopted to prevent accidents in Belgium in 1851, and has 
attended scores of accidents from explosions in his own districts and 
in other districts to which he was invariably sent by the British 
home office in case of serious accident, does not believe that any ex¬ 
plosion is due to dust and dust only. This remark is intended to 
convey the idea that there still exists some doubt among authorities. 

Your correspondent went with Mr. Dickinson to Risca, South 
Wales, when 120 men were killed on a night shift in May, 1880. It 
was endeavored to be put forth that lightning passing down the 
steel wire rope guides of the upcast or fan shaft had been carried 
along the return airways and ignited the gas. A vivid flash of light¬ 
ning and .a loud peal of thunder occurred just about the time of the 
explosion, and this was the ground for the supposition that lightning 
had done the mischief. 

The facts were against this theory and subsequent experiments 
disposed of it beyond doubt. 

Other causes were found for this explosion. Your correspondent 
would observe that the interior workings were much more seriously 
damaged than Monongah. Dismembered bodies were very numerous 
and in one case a boy was driven against a coal wall some distance 
from where he had been standing and his body stuck on the side of 
the road is bas-relief with his crushed lunch basket under his arm. 

Dust here undoubtedly contributed to increase the scope and force 
of the explosion which visited every part of the pit and killed every¬ 
body in it. 

Penygraig, a more fatal explosion, followed in a few weeks. 

Newport Abercarne, working the same seam and only a mile 
away from Risca, exploded a year before with a death roll of 260. 

In these and many other cases where the evidence of a volume of 
gas sufficient to secure so serious consequences was entirely wanting, 
and the pits in which they took place were worked exclusively with 
locked safety lamps which were supposed to be safe, an outburst of 


MINING ACCIDENTS. 3 

gas was usually fallen back upon as a cause, but in no case was there 
evidence of an outburst having taken place. 

It was in 1882 when the Marquis of Londonderry’s Seaham pit 
exploded, with a loss of life of over 250, that the Government caused 
an inquiry to be made into the effect of dust on colliery explosions. 

Sir Frederick Abel, the Government chemist at Woolwich Arsenal, 
conducted a series of experiments with dust obtained from Seaham 
collieries and many others. One curious result was observed: Air 
mixed with a percentage of fire damp so small that an ordinary 
safety lamp would not show it, was found to produce explosions by 
introducing a mixture of “ stone dust;” that is, slate dust containing 
no coal. This stone dust was taken from the floor of underground 
roads of Seaham colliery. 

About this time in England many mine managers and superintend¬ 
ents collected dust and tested it, sometimes with results that were 
surprising. In the dust we collected in the Midland district, that 
which most readily ignited by firing a double or improperly tamped 
single shot into it was from a seam of coal that had never been 
known to make gas in the mine. 

Numerous experiments prove that 1 per cent of fire damp mixed 
with 99 per cent of air can not be exploded by a blown-out shot; but 
if there is dust in this atmosphere it can be lighted by the ordinary 
lamp which a miner carries in his cap. 

Fire damp in air unmixed with dust will not burn when a naked 
light is introduced into it unless the fire damp is as much as 6 per 
cent of the whole volume. 

There is no doubt whatever that under some conditions a blown-out 
shot will ignite coal dust if the coal dust is in a sufficiently fine state 
of division. It requires a nearly white heat to do this, but if fire 
damp be present ignition takes place at a temperature lower in pro¬ 
portion as the volume of fire damp is increased. Therefore a per¬ 
centage of gas present not discoverable by a fire boss with a Davy 
or other ordinary lamp seriously increases the danger of blasting in a 
dusty mine. 

The broad facts as to the explosive power of dust have been known 
for a long time. In their relation to explosions in coal mines, atten¬ 
tion was first officially directed to them in the report of Sir Charles 
Lyell, the geologist, and Farady, the electrician, on the explosion at 
the Haswell colliery, county of Durham, England, in 1847. 

You may remember that about 1877 a candy factory in New York 
blew up by the ignition of sugar dust, killing some 50 or 60 girls. 

I notice in visiting the large maltings at Burton-on-Trent, Eng¬ 
land, where Bass’s ale is made, the entire end of several buildings in 
which the grinding of malt is done are constructed of iron plate 
doors, poised on trunnions so delicately that a man could push a door 
of several tons weight partly open. The manager explained that 
some years before a piece of flint among the malt being ground had 
struck fire on the steel rolls of the mill, causing an explosion which 
had blown out the end of the building. 

Explosion is only rapid combustion and depends largely in its 
incipient stages on the fineness of the dust. 

In New Jersey the manufacturers of Alpha cement have turned 
this property in small coal, which dust really is, to account. The 
cement, rock, and coal are ground fine and blown into a circular fur- 


4 


MINING ACCIDENTS. 


nace which revolves and is lined with refractory material. A con¬ 
tinuous flame is maintained inside, and by the time the cement and 
coal have reached the end of the furnace the cement has been per¬ 
fectly calcined, a process which took days under the old method of 
calcining before grinding. 

In coal mining we use a chain machine. The undercut is 4 inches 
thick, so that for every square yard undercut we grind 3 cubic feet 
of the finest coal into dust. This dust weighs at, say, 80 pounds per 
cubic foot, 240 pounds. A seam of coal 6 feet thick after being un¬ 
dercut at 4 inches from the bottom leaves 5 feet 8 thick. This at 80 
pounds per cubic foot weighs 4,080 pounds of coal. The total yield 
of coal and dust is 4,320 pounds for every square yard of coal seam 
removed. We make 240 pounds of dust or 5.55 per cent of the total 
product of the seam. This dust, by the tramping of men’s and mules’ 
feet and other disintegrating agencies, we reduce to a still finer state 
of division and thence more dangerous. We leave it in the mine. In 
a mine that makes the smallest possible quantity of fire damp, or 
w T here unskilled blasting takes place, we have in thifc dust the crucial 
element of a disaster. The conjunction of conditions which come to 
every mine at some time or another are all that is needed to bring it 
about. 

Experience has shown that the most violent explosions have oc¬ 
curred in new mines that are being vigorously worked. In the United 
States the explosions of Pocahontas and Monongah will bear out this 
view, and are supported by numerous instances of explosions in 
England where the stage of development was similar. 

The reason for this is evident to any person who has considered 
the subject. All coal gives off a portion of its volatile matter when 
exposed to air. Large coal does it slowly, the skin being affected first. 
Dust, through being in small particles, gives off its hydrocarbons 
more quickly, but when laying in heaps or layers it is some time be¬ 
fore the particles inside have parted with their most inflammable 
elements. So long as they retain thees elements they are much more 
sensitive to explosion than dust which has parted with them. There¬ 
fore a new mine laying down in its entries and rooms over 5 per cent 
of its total output in the shape of inflammable dust is more likely to 
explode than a mine which by slower development has had portions 
of the same amount of dust longer subject to the influence of fresh 
air. 

Old dust will carry an explosion, but it requires new dust to propa¬ 
gate it. 

The subject is new to us in this country, as it was to coal men 
abroad a little over twenty years ago. 

Our mines have hitherto been comparatively harmless. The neces¬ 
sity for diffusion of knowledge upon these subjects has now been 
forced upon us. Its possession was hitherto supposed to be the pre¬ 
rogative of bosses only. A few thoughtful men saw the necessity of 
knowing when fire damp was present in a mine in small quantities. 
Professor Ansell in England devised an apparatus for estimating 
small quantities of fire damp in the air of a mine fifty years ago. 
This instrument and others since designed depended upon the lu¬ 
minosity of platinum wire heated in the presence of hydrogen, a 
phenomenon to which attention was called by Sir Humphrey Davy 


MINING ACCIDENTS. 


5 


in his researches, which ended in the invention of the safety lamp 
in the year of our Lord 1815. 

Lamps burning alcohol show a cap when placed in an atmosphere 
containing fire damp in such small proportions that the oil or gasoline 
burning safety lamp will not detect. 

Dr. Frank Clowes, an English professor of mining at Nottingham 
University, has devised a lamp burning hydrogen, which is com¬ 
pressed in a vessel forming the handle of the lamp. This lamp will 
detect the smallest amount of fire damp which any apparatus adopt¬ 
ing the method of flame can detect. Doctor Clowes places inside 
the lamp a scale or ladder, the marks on which indicate roughly the 
portion of fire damp present. 

Your correspondent was the first to apply this last principle, 
which was publicly enunciated in a paper read for him by Colonel 
Hollingsworth before the Manchester Geological Society in 1886. 

A number of methods of analysis have been devised. Doctor Shaw, 
of Philadelphia, has a machine, but it is too cumbrous and far too 
costly for common use. 

At Port Royal, in 1893, your correspondent used the Goodwin 
apparatus, which is very simple but requires three or four manipu¬ 
lations for one determination, its principle being to determine the 
residual hydrogen. 

Much better things are now in use. For instance, the Le Chatelier 
eudiometer, a simple and cheap apparatus, easily operated. Col¬ 
lecting the gas is effected by the use of a common glass jar with a 
rubber cork with two glass tubes in it. This is taken into the mine 
full of water. The water is let out of one of the tubes and the air of 
the mine to be examined enters the other. It is taken outside and 
tested. In some fiery French mines this is done every day. 

We have reached that point when we have to know how much fire 
damp is contained in the air of working places every day. The 
means of ascertaining this are simple. 

We have to make the knowledge of gases met with in mines and 
the physical principles of ventilation as easy to learn as the knowl¬ 
edge of dollars and cents, if not quite as natural. 

It appears to me to be our duty to teach elementary mining chem¬ 
istry to miners’ boys, accompanied by demonstrations which interest 
and take hold upon the young mind. 

Forty years ago the science and art department at South Kensing¬ 
ton, London, sent out a few lecturers, who established science and 
art classes in industrial centers. Out of these grew the mining 
lectures conducted or directed from university centers. The estab¬ 
lishment of county councils in England (an extended form of county 
commissioners) placed this teaching on a permanent basis. A lec¬ 
turer goes one night a week to each of half a dozen mining villages 
and lectures with very plain demonstration. Next week, preliminary 
to the lecture, pupils are examined. This applies to men and boys 
who work during the day. 

I will be glad to assist in any way I can whenever called upon. 

I remain, dear sir, yours, very truly, 

William Clifford, 

Jeannette , Pa. 


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